As I've mentioned a couple other times, 2013-14 was a bit of a comeback year for several areas that had been on the downturn in recent years, like the CW and Friday nights. The 10:00 hour was another example, as it grew to its biggest average ratings in five years in each half-hour. Why? It's been an hour lacking in major success stories in recent years, but three of broadcast's biggest 2013-14 successes came in the hour: top drama Scandal, top newbie The Blacklist, and sophomore bouncer Chicago Fire.
Another interesting note is that the 8:00 hour actually outrated 8:30, something that's never really been the case in the past. Usually, the major jump in viewing levels makes the difference. A big part of this trend comes from weaker retention by half-hour series; the shows airing after 8:00 occupants like The Big Bang Theory and How I Met Your Mother were weaker than usual this season. Perhaps the typical one-hour or two-hour series is not jumping as much at 8:30 as in the past, but I haven't done enough number-crunching to make a call on that. More on that another day!
Here's the now updated A18-49+ Time of Day post.